With regard to the distance learning studies, it is fine to do it this way. One tip is to get hold of the Bristol Ground School Online Question Bank.
This will prep you up for the exams. Hammer it out and hammer it out!! You will pass the exams thats what counts! HOWEVER, once you have passed them all and the time pressure etc is off, you can then go thorugh them all again, and LEARN it all at slow pace! In your own time, just what I'm doing now.
I passed them all last year but have always got my head in a book. I probably know more now than I did then!! It would be foolish not to have the professional knowledge required (hence the after exam study!), its vital. But for passing the exams.... (at the end of the day they just a hurdle) Knowledge is for life!